1. Field of the Invention
The present invention relates to a one-piece resin component for a dynamoelectric machine and a manufacturing method that uses such a one-piece resin component.
2. Description of Related Art
According to a previously known manufacturing method of an article (e.g., a tandem pneumatic booster), a housing (e.g., a shell) of the article is configured into a shape that enables easy stacking of such a housing with one or more of such a housing to form a stack of the housings, and the stack of the housings is transferred together to an assembly line at once to allow a reduction in transferring costs of the components and thereby to allow a reduction in the manufacturing costs of such an article (see, for example, JP2002-321610A that corresponds to U.S. Pat. No. 6,637,838B2).
In a technical field of a dynamoelectric machine (e.g., a geared electric motor), a gear housing of the dynamoelectric machine, which receives a worm wheel and a worm, is mass-produced through a resin molding process in a molding factory. Then, the mass-produced gear housings are transferred to an assembly factory to assemble the gear housings with the other components to produce the dynamoelectric machines. At the time of transferring the gear housings from the molding factory to the assembly factory, the gear housings are stacked one after another in a stacking direction (axial direction) to form a stack of the gear housings. In order to facilitate the stacking of the gear housings, it is conceivable that a first side engaging portion and a second side engaging portion (serving as stackable engaging portions) are directly formed in a first axial end part and a second axial end part, respectively, of a wheel receiving portion of the gear housing, which receives the worm wheel. The first side engaging portion of one of the gear housings is engaged with the second side engaging portion of another adjacent one of the gear housings to stack these gear housings together in the stacking direction, and this process is repeated for the rest of the gear housings in each stack. Then, the stacks of the gear housings are transferred from the molding factory to the assembly factory.
Lately, there are demands of increasing the rigidity of the gear housing and of implementing required functions of the gear housing. In order to satisfy these demands, a shape of the gear housing tends to be complicated. When the first side engaging portion and the second side engaging portion are directly formed in the gear housing, a design freedom of the gear housing is disadvantageously limited, and it is often difficult to implement the required functions in the gear housing. Furthermore, in a case where the first side engaging portion and the second side engaging portion are not formed in the gear housing, a cushion member needs to be placed between each adjacent two of the stacked gear housings to limit wobbling of the stacked gear housings during the transportation. In such a case, the cushion member is additionally required, and a step of placing the cushion member is additionally required. Furthermore, the stacked gear housings may not be neatly aligned in the stacking direction. That is, some of the stacked gear housings may protrude laterally on the left side or the right side or on the front side or the rear side. Therefore, the stacked gear housings tend to occupy a larger space in a transfer case (container), which accommodates the stacked gear housings for the transportation purpose. Thus, the number of the gear housings, which are receivable in the transfer case, is disadvantageously reduced.